-- The ability to generate tiny three-dimensional objects using a special printer just got a whole lot faster.
Machines, known as two-photon lithography printers, can produce detailed structures as small as a grain of sand.
Vienna University of Technology researchers Jan Torgersen and Peter Gruber, led by materials science and technology professor Jürgen Stampfl, took the printing process from millimeters per second to five meters per second, a world record.
This 3-D printed version of St. Stephan's Cathedral in Vienna is about 50 micrometers wide on its largest side, smaller than the diameter of the average human hair.
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Vienna University of Technology

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The printing process works by focusing a laser beam onto liquid resin. Mirrors guide the beam to solidify lines of the resin into solid polymer. Line by line, a layer is built. Each structure consists of numerous layers.
The scientists use a new resin, developed by chemistry professor Robert Liska, that could be solidified anywhere, not just on top of the previous layer. They also used faster electronics and rotating mirrors that had improved steering.
This is a 3D image of the "Wormser Tor," the city gate leading into the historic German town Frankenthal, which was first settled in the 8th century.
The scientists designed it from original photographs and their resulting print has never been published until now, Torgersen told Discovery News.

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This race car is about 285 micrometers wide, according to Torgersen. While still small, it's several times the width of a human hair.
In the field of two-photon lithography printing, he calls their record-breaking printer a significant step closer to real applications and commercialization.
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The goal was to speed up the process in order to make this type of printing more attractive as a technique, as well as more cost-effective.
Usually the speedy printer was occupied with the scientists' experiments instead of producing recognizable images, Torgersen said. But they did have some fun in demonstrating its capabilities, like this image of a man.
Tiny, intricately printed 3-D structures could have a number of different applications. For example, they could be used in medicine to make scaffold for living cells in order to build tissue.
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Here, they replicated the Tower Bridge in London. Torgersen said he and his colleagues plan to focus on water-based biopolymers for biological applications. They currently have a paper on using hydrogels for the printing process under revision.
"We hope we can motivate potential partners from the biology side to work with us," he said.
BLOG: How To Make Nano-Origami

Klaus Cicha

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Jan Torgersen and Peter Gruber
Researchers Jan Torgersen (left) and Peter Gruber (right) stand next to the printer.
The printer is part of a project called Phocam to develop new 3-D printing technology with industry partners.
PHOTOS: Extraordinary Beauty of the NanoArt World

First, a word (make that words) about transmissions: in the most general sense, a transmission is the thing that turns the power output of a motor into some combination of speed and torque. Usually, the way a transmission works is that you can trade torque for speed (or vice versa) while optimizing the efficiency of your motor: in automobiles, a low gear gives you lots of torque but limits your top speed, while a high gear gives up torque to let you go faster.

Most automobiles have discrete gearboxes, where you can choose from some number of fixed gear ratios. Inevitably, this means that most of the time, the transmission is not optimized for what you want to do. A continuously variable transmission, on the other hand, offers an infinite number of gear ratios over a fixed range.

Anthony sits down with Bernie Peyton, a wildlife biologist and talented origamist, to discuss how his research and art fit together.

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Unlike most automobiles, most robots don't bother with transmissions at all, because they're heavy and complicated. This means that robots have to be designed to either move fast (which doesn't require a lot of torque), or haul stuff (which does), but they're not great at doing both.

The researchers designed an origami wheel that can do both, by simply changing its radius, and thanks to its origami design, it does this by itself. It's a completely automatic continuously variable transmission, which allows a small robot to either move fast or haul stuff without requiring any additional complexity beyond an origami wheel.

There are three robots in the video below. There's one with big fixed wheels (high speed, low torque), one with small fixed wheels (low speed, high torque), and then one with origami wheels that can expand and shrink. No adjustment is necessary: if the origami wheels have too much load on them to rotate, they stall, and as the wheel hubs continue to turn, the wheels collapse, which increases their torque until they can move:

To reiterate, this transmission is both continuously variable and completely automatic. The wheel can adopt any effective gear ratio in the range between its minimum and maximum diameters, and it does this passively like a spring, as it responds to loads on it by shrinking its diameter until it achieves the maximum diameter at which it can consistently rotate.

The cost of the origami wheel is 70 percent of the cost of a fixed diameter wheel, less whatever it costs to hire someone who knows what they're doing to fold it up for you. The researchers suggest that it would also be ideal for applications where weight and volume are issues, like interplanetary rovers, as the wheel can be folded up and then deploy itself.